In known fuel injectors, fuel filters are pressed into a fuel-intake nipple and affixed therein by a brass ring. This manner of fastening, first of all, involves the risk of abrasion and the formation of chips, which can lead to malfunctions of the fuel injector. On the other hand, the use of expensive brass as a component material is a cost factor that considerably increases the cost of the fuel injector.
A fuel injector, in which a fuel filter is manufactured in one piece with a retaining collar, is described in German patent document DE 43 25 842. The retaining collar radially extends beyond the fuel intake nipple and has a lip outside the fuel intake nipple. The circumferential lip of the retaining collar, together with a groove on the outer circumference of the fuel intake nipple, forms a snap-in connection by which the fuel filter is fastened in a defined manner. Only a clearance fit exists between the base element of the fuel filter and the inner wall of the fuel intake nipple, so that any build-up of shavings in the interior of the fuel injector is prevented.
A particular disadvantage of the fuel injector described in German patent document DE 43 25 842 is the large amount of processing time spent in affixing the filter to either the adjusting sleeve or the fuel intake nipple. In addition, the filter and adjusting sleeve are made of different materials, whereby shavings and abrasion are formed at the contact surfaces, predominantly on the plastic of the filter, which can lead to malfunctions of the fuel injector due to the deposition of the particles.